Oscillator mounting



1933- R. L. WILLIAMS ,9

OSCILLATOR MOUNTING Filed July '7, 1928 v 2 Sheets-Sheet 1 IN VENT 0R Robe/w Z. MOI/10m s ATTORNEY Patented Aug. 22, 1933 enses Purser omcs OSCILLATOR MOUNTING Robert Longfellow Williams, Newton, Mass, as-

signor to Submarine Signal Company, Boston, Mass, a Corporation of Maine Application July 7, 1928. Serial No. 291,070

2 Claims. (c1. 177-386) The invention of the present application concerns the mounting of sound producing means and receiving means on a vessel. 7

Many types of mounting have been tried upon vessels, but all seem to be under some disability when a ship is moving very rapidly through the water. This difiiculty has never in the past been well understood. It was for the most part attributed to water noise and is no doubt due to some extent to water noise. However, I have recently discovered that in the mounting of sound producers upon a. vessel, apparently the signal received by a receiver on the same vessel varied in strength not only depending upon the position of the sound producer upon the vessel but also upon whether the vessel was moving or standing still.

Further investigation has shown that when a vessel is moving through the water, the water is so churned up by the movement of the vessel and by the propeller that great quantities of air are mixed and churned in the water. This air often gives the, water a whitish appearance from the numerous little bubbles formed therein and sets up in the vicinity of the vessel an excellent air screen through which the sound from the sound producer finds dlmculty in penetrating. Thus, not only is it difilcult to get the sound into the water, but it is also dimcult to get the sound back to the ship to the sound receiver.

This difficulty exists for the most part in fast boats making over eighteen knots, although it is present in boats moving less rapidly, depending to a good extent upon the design of the vessel.

I have further discovered that upon almost all boats there is a section which is particularly free from this blanket of air bubbles which so completely blocks the sound passage, and that this section extends from just before the stern of the vessel to a distance of about ten or fifteen feet in the oi the stem upon each side. The stem of the vessel apparently piles up the water it for a slight distance, and this water not spill over untila distance from about ten to fifteen feet from the stem. llp parently after this point the water begins to spill over and churn great quantities of air into it. By placing the sound producing means in this region also the sound receiving means, it is possible not only to get the sound into the water but also to receive it.

This expedient is very useful and helpful, not only in accoustic depth sounding, but also in communication by sound and in giving warning signals. The invention will be better understood by reference to the drawings showing a. number of embodiments of the invention, in which Figure 1 shows a sound producing system mounted just to the rear of the stem 0! the vessel,

Figure 2 shows a sectional view of Figure 1,

Figure 3 shows a sound producer or receiver mounted forward of the stem,

.Figure 4 shows a sectional view through the device shown in Figure 3,

Figure 5 shows a sound producer mounted on the stem,

Figure 6 shows a sectional view of the device shown in Figure 5,

Figure 7 illustrates a mounting by building out the stem of the vessel,

Figure 3 illustrates a section through Figure 7, and Figure 9 shows a section through the sound producer.

The ship 1 shown in Figure 1 has mounted in the lower part of the bow vertical with and Just behind the stem 2 two sound producers 3 and 4 which may be submarine sound oscillators as shown in Figure 9. The oscillator is composed of two'plate-like elements recessed between outer rims -18 and s9 and having two diaphragms 40 and ii. The diaphragms are vibrated by means of the armatures 43 and energized h the coil 45, the armature 43 being attached to the diaphragm 40 in a welded joint 44, and the armature so, similarly, to the diaphragm -21 by the welded joint 51. The two plates are held together by the bolts 46 in a watertight joint because of the gasket 47. Each diaphragm moves in the same phase, inwardly together and outwardly together and substantisily the Whole efiective surface of the dla= phragm takes part in this motion.

The oscillators having similar diaphragms on can be used to produce or receive sound waves. Cihis is shown better in the sectional view of Figure 2, where both faces 7 and 8 of the oscil= later i are exposed to the sound transmitting medium. The oscillator 4. is set in the opening in the boot and the frame pieces 5 and 6 are provided to make a stream line how for the water rushing by.

In the modification shown in Figures 3 and e, the oscillator 3 is mounted on the lower part of the stem by means of a bracket 14 which holds the oscillator by means of the bolts 15 about the face of the bracket and which is bolted or riveted to the boat by means of the bolts or rivets 16. This type of mounting is sometimes preferable to the type shown in Figure 1, since the skin of the vessel need not be cut away in mounting the oscillator on itand also because the oscillator is in a somewhat better acoustic position with reference to the air blanket mentioned above. The oscillator can be made stream line and no diillculty will be encountered on account of carrying the water away from the plates.

Figures 5 and 6 show a still further modification in the mounting of the oscillators on the vessel. Here the oscillators 20 and 21 are mount- -ed exterior on the stem of the vessel in a posihas only one active diaphragm; as shown in Figure 5 there would be four oscillators used.

Figure 7 shows a form of construction which is preferable in many ways to the forms illustrated in the prior figures particularly on account of the strength it affords and also on account of the preservation of the general stem and keel contour of the vessel.

- In this modification plates 30 are bolted, riveted or secured in some well known manner to the side of the vessel, as by the bolts 31, just adjacent to the stem on the lower part of its curvature, as indicated in Figure 7. In effect, the plates are so shaped as to round out the stem of the vessel and make no abrupt change in its contour, thereby preventing possible chance of damage to the oscillator and at the same time furnishing a better stream line effect to the stem of the vessel. The plates 30 are provided with an opening in which the oscillator 3 sets. The oscillator itself in this modification has a flange 34 lower than the surface of the diaphragm oi the oscillator by the thickness of the plates 30, so that the oscillator diaphragm surface and the plates may be flush and make a continuous even surface. The oscillator is firmly secured in the opening by means of the bolts 32 or other suitable means.-

This form is also very advantageous to employ because it does not interfere with the dock ing of the vessel. The plate 30, it will be noted, is entirely within the straight line of the stem and the straight line of the keel, so that none of the beams used in supporting the vessel in dry possible except when the vessel was proceeding at very slow speeds.

In addition to the features above described, the oscillators may be mounted vertically on the stem or beside it, and thus increase the intensity of the sound component in a horizontal direc tion. It will be noted that the particular mounting herein described makes such an intensified horizontal component possible.

Having now described my invention, 1 claim:

1. In combination, a vessel, a sound app ratus, and means for mounting the same comprising a pair of plates secured to the sides of the vessel adjacent to the stem and entirely within the straight lines of the stem and the keel and means for mounting said sound apparatus between said plates.

2. In combination, a vessel, a sound apparatus and means for mounting the same. entirely within the straight lines of the stem and the keel comprising a pair of plates provided with aligned openings and means for mounting said so apparatus in said openings.

ROBERT LONGFELLOW WILLIAMS. 

